1. Technical Field
The present invention relates generally to security devices for entry ways, and more particularly to a security chain which spans a doorway for limiting inward motion of the door.
2. Background
Most doors or other entry ways are typically secured with a hand set or a combination of a hand set and lock set which allows the door to be latched when closed or, in the alternative, to be both latched and locked when closed. The disadvantage of this arrangement is that an occupant, in order to ascertain the identity of an individual or party on the other side of the door, typically unlocks and/or unlatches the door and opens the door partially at which point the door is entirely unrestrained from further opening, other than the physical restraint which the occupant may be able to apply against the door. Additionally, when the sole means of securing the door consists simply of either a hand set, lock set or a combination of the two, effectively there is a single point which restrains forced entry; namely, the point at which the latch or the bolt on the lock penetrates the door frame.
A variety of door security devices are well known. Most notably common and most often seen is the keeper which consists of a short chain typically six to ten inches long, having a first end attached to the door and a second end which may be removably attached to a keeper fixture of some sort permanently attached to the door frame or door jamb. While this arrangement is inexpensive and simple to install, it provides little security, simply because the door which is either open to view through while restrained by the chain, or a door which is locked or latched, once the latch or lock is broken, the door is free to travel the six to ten inches which corresponds to the length of the chain before the security system offers any further restraint. In that distance alone, a door, if adequately forced, can easily tear the chain from its anchorings either at the door frame or on the face of the door.
Kohn, U.S. Pat. No. 977,316, describes and claims a door securing device comprising a door securing bar, an abutment on the floor against which the lower end of the bar is set, with a locking slide-in plate which is mounted on the door having a keeper through which the second end of the bar passes. The second or top end of the bar is secured by a locking slide which, when in the locked position, holds the second end of the bar securely against the door restraining forced entry and which, when in the open or unlocked position, allows entry. Unlike the present invention, Kohn does not allow a door to be partially opened while still providing security or restraint.
Other means for clamping and securing openings have been described and/or claimed. In Winter, U.S. Pat. No. 3,473,598, an improved gate fastener is described.
Olson, U.S. Pat. No. 2,628,397, describes and claims a hold-down clamp for attachment to the body of a truck or trailer which provides a means for holding a load placed on the truck or trailer snugly in contact with the bed of the truck.
Haist, U.S. Pat. No. 4,564,230, describes a restraint apparatus for a cargo box having a pair of doors. The restraining apparatus consists essentially of a leash having means for attachment at either end, the first end attached to the first door latching means and the second end connected to the second door latching means. This restraint apparatus is configured so that in the event a portion of the load contained within the cargo box has fallen against the inside of the door, the door will be restrained from swinging open uncontrolled.
None of the described devices provide the advantages of the present invention, namely, providing a security means for a door or entry way which is secured to the frame on either side of the door, thereby providing a more substantial anchor, together with the feature which allows the user to adjust the tension across the security device, allowing the door to be opened slightly, together with the feature which allows the retaining device to be clamped tightly across the face of the door, effectively providing two additional points of restraint.